1. Field of the Invention
This invention lies in the field of polyethylene pipe construction. More particularly, this invention lies in the area of the joining of large diameter pipes by means of heat fusion butt apparatus. Still more particularly, it involves apparatus utilized for the purpose of removing, or cutting away, the internal beads that form when two lengths of polyethylene pipe are joined by fusion.
2. Description of the Prior Art
In the joining of polyethylene pipe by the fusion method, there is naturally a tendency for heat softened material, at the mating surfaces, to be squeezed radially inwardly and outwardly to form beads. The internal beads are troublesome because they may extend inwardly a distance of 1/16 or 1/8 of an inch and, therefore, reduce the diameter at each joint. They thus cause a resistance to flow of fluid through the pipe. In particular, in the newest developments in transporting large objects such as oranges, or other fruit or vegetables, or mechanical objects, or minerals, it is important, for reasons of power requirements, to provide as smooth an interior surface as possible. It is, therefore, important to remove the internal bead, prior to completing the construction of a line using segments of polyethylene pipe.
In the prior art, there is no satisfactory method, at present, for machining or cutting away the internal beads which form when the sections of pipe are joined by fusion.